The invention concerns a locking screw according to the preamble of patent claim 1. Such a locking screw is known for example under DE-PS No. 27 26 671 from the same applicant, and is, after all, a commonly used locking method for the adjustable connection of a hinge strap to a base plate. In order to ensure a strong contact and a strong support between the locking screw and the assembly plate, a sharp edged ridge is formed on the end face of the threaded portion of the screw which is designed to cut into the material of the assembly plate thus achieving a stronger seating.
Because the material of the assembly plate is relatively soft and because of the varying loads on the hinge, the ridge on the screw digs into the plate, cratering it, and thus the screw loosens and has to be retightened after the hinge has been used for some time. In extreme cases, the hinge can come right off the assembly plate because of the loosened screw.